pr12007.cpp

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////////////////////////////////////////
// File Name: pr12007.cpp
////////////////////////////////////////
#include <iostream>
#include <cstring>

////////////////////////////////////////
// The String class.
////////////////////////////////////////
class String
{
    char* sptr;

public:
    String(char* s = 0);
    ~String() { delete sptr; }
    void display()
        { std::cout << sptr << std::endl; }

    // Overloaded [] operator.
    char& operator[](int n)
        { return *(sptr + n); }
    const char& operator[](int n) const
        { return *(sptr + n); }
};

// The String class constructor.
String::String(char* s)
{
    if (s)
    {
        sptr = new char[std::strlen(s)+1];
        std::strcpy(sptr, s);
    }
    else
        sptr = 0;
}

////////////////////////////////////////
// The main() function.
////////////////////////////////////////
int main()
{
    String string1("The Ides of March");
    string1.display();

    // Change some string characters.
    string1[4] = '1';
    string1[5] = '5';
    string1[6] = 't';
    string1[7] = 'h';
    string1.display();

    // Change a substring.
    strncpy(&string1[4], "21st", 4);
    string1.display();

    // const string, cannot be modified.
    const String string2("Et tu, Brute?");
    for (int i = 0; i < 13; i++)
        std::cout << string2[i];

    return 0;
}